The present invention relates generally to shelf-type storage rack systems, particularly an improved cross-bar that extends between the front and back beams supporting shelves and that is readily removable and reusable.
Shelf-type storage racks typically include at least four vertical posts or columns at each corner of a rectangle. The posts are interconnected by generally horizontal deck beams which extend horizontally between two adjacent front posts and between two adjacent back posts. Shelves are supported on the horizontal deck beams. If the load carried by the shelves is heavy then cross-bar supports are added that extend between the front and back beams, generally in the same plane.
One way of creating the storage shelves is the use of wooden slats that extend between the deck beams. In order to keep the slats from being moved along the axis of the slat the front and back deck beams are typically roll formed to provide a ridge or lip or notch on their upper surface of opposing deck beams upon which the wooden slats are placed. The specially formed beams must be configured to accommodate the specific thickness of the slats or else the surface formed by the slats is offset from the surface of the deck beams and boxes of items placed on the slats may be above or below the deck beam. If the surface on which the boxes rest is below the deck beam then the beam impedes removal of the box. Further, the slats may be knocked-out, skewed or otherwise misaligned between the deck beams, causing the slats to fall and the shelf to be weakened. It also requires specially shaped deck beams. Thus, there are disadvantages such as increased construction costs and decreased flexibility.
If the deck beams and shelves are heavily loaded the deck beams sag toward the center and there is some tendency for the cross-bars supporting the shelving rack to bow in such a way that they either move apart or possibly disengage from the deck beams. Moreover, problems may arise because of irregularities in the floor on which the storage rack is placed, which irregularities cause the posts to lean further apart than intended and that in turn can cause unexpected spacing problems between columns and between deck beams. These spacing errors, along with errors in the length and width of the beams and columns can result in the creation of variable distances between deck beams that can cause difficulties in assembling and fastening the parts together to form the storage racks, especially in fastening cross-bars to opposing, front and back deck beams. There is thus a need for an improved system for attaching cross-bars to opposing deck beams to create the framing for storage shelves. The is also a need for an improved cross-bar that is readily removable and reusable yet can be locked or secured against undesired movement and rolling to create a shelf that properly supports loads.